Electromagnetic switch



y 28, 1959 I c. F. BRAUNECK 2,897,316

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ATTORNEY United States Patent Ofiiice 2,897,316 Patented July 28, 1959ELECTROMAGNETIC SWITCH Charles F. Brauneck, Glen Cove, N.Y., assignor toMurray Manufacturing Corporation, Brooklyn, N.Y.

Application September 4, 1957, Serial No. 682,023

Claims. (Cl. 200- 104) This invention relates to an electromagneticallyoperated switch which is particularly useful in motor control devices.

An electromagnetic switch is essentially a contacting mechanism, theopening and closing of which is controlled by an electromagnet.

In general, electromagnetically operated switches are classified eitheras Vertical Lift Armature or Clapper Type. In the vertical lift armatureswitch, the motion of the armature is in the vertical plane, thecontacts are in the horizontal plane and the electromagnet pulls thearmature up to close the contacts. The contacts are opened by force ofgravity.

In the clapper type switch the motion of the armature is pivotal aboutthe lowest edge of the armature, the contacts are in the vertical planeand the electromagnet pulls the armature to close the contacts. Thecontacts are opened by force of gravity augmented by a spring.

Each of the above-mentioned switches has certain disadvantages. Forexample, in the vertical lift switch, the supporting base is located ina plane parallel to the direction of the operating forces. Therefore,the switch is subjected to tension and shearing forces. This requiresthe construction to be sufficiently heavy and rugged to withstand theseforces. The size of the switch is, therefore, rather large to preventmechanical failure.

Accordingly, it is an object of this invention to provide a compact,relatively simple electromagnetic switch.

It is a feature of this invention to provide a switch of uniqueconstruction in which the forces operate into the plane of the basesupporting the device. Thus, the construction may be made lighter andyet is mechanically more rugged than the known switches.

It is a further feature of this invention to provide such a switch,which is constructed so as to permit ease of wiring, inspection andmaintenance.

It is still a further feature of my invention to provide anelectromagnetic switch which can readily be converted to a motorcontroller by adding overload relays in line with the switch, anauxiliary contact mechanism on either side of the switch and a pushbutton control on top of the switch.

In accordance with an aspect of my invention, there is provided anelectromagnetic switch comprising a base member, preferably mounted inthe vertical plane, and a pair of side members attached to oppositesides of the base member. An electromagnet is mounted on the base memberbetween the side members and drives an armature spaced in cooperativerelation therewith. The direction of movement of the armature is in aplane perpendicular to the base. An insulating bridge member is mountedon the side members and supports a plurality of stationary contactsmounted in spaced and aligned pairs. One side of the pairs of contactsis connected to the line and the other side to the circuit to becontrolled. A plurality of bridging contacts are provided for contactingand shunting respective pairs of the stationary contacts. The bridgingcontacts are supported on an insulator carrier which is attached to thearmature. The armature is normally urged into a position in which thebridging contacts are separated from the stationary contacts. When it isdesired to close the stationary contacts, the electromagnet is energizedand the armature is drawn to a position in which the bridging contactsengage the stationary contacts.

The above-mentioned and other features and objects of this invention andthe manner of attaining them will become more apparent and the inventionitself will be best understood by reference to the following descriptionof an embodiment of the invention taken in conjunction with theaccompanying drawings, wherein:

Fig. 1 is a front view of one embodiment of the electromagnetic switch.

Fig. 2 is a cross-sectimonal view taken along lines 2-2 of Fig. 1;

Fig. 3 is a cross-sectional view taken along lines 33 of Fig. 1;

Fig. 4 is a front and top View of a frame designed to support anarmature of the switch;

Fig. 5 is an end View of an insulator bridge member;

Fig. 6 is a cross-sectional front and top view of contact supportingmeans; and

Fig. 7 is a front and end view of a cover for the switch.

Referring first to Figs. 1-3, the electromagnetic switch comprises aflat base member 1 for supporting the switch components, and isadaptable for mounting in the vertical or horizontal planes. However, inaccordance with the preferred embodiment, the mounting position is inthe vertical plane, and the following description will contemplate suchmounting.

Attached rigidly to the base 1, are a pair of C-shaped side members 2,3. The side members 2, 3 are positioned at opposite sides of the base 1facing each other.

An electromagnet comprising an E-shaped core 4 is mounted to the basemember 1 between the side members 2, 3. For mounting, the core isprovided with slides which fit snugly under flanges of the side members(Fig. 1). In addition a lug 5 is struck-up from the base which isprovided with a tapped hole for a screw 6 which passes through a hole inthe core 4 and is threaded into the lug 5. As shown, the legs of thecore 4 extend perpendicular to and away from the base 1.

A coil 7 is positioned around the center leg of the core and extendsbeyond the end 8 thereof.

The electromagnet acts upon an armature 9 movably mounted in cooperativerelation with and located in front of the core 4. The armature is in theform of a similar E-shaped core member with the legs thereof alignedwith the legs of the core 4-. The center leg 10 of the armature core isadapted to move into the extending portion of the coil 7.

The armature 9 is supported by a U-shaped frame member 11 (Figs. 2, 4).The cross-arm 12 of the U is provided with flanges 13 which engage theopposite sides of the armature core 9. The frame is secured to the corepreferably by rivets, such as shown at 14 in Fig. 3. The legs 15, 16 ofthe frame extend towards the base member and comprise flanges 17, 18respectively at the ends thereof, extending toward the side members.

The movement of the armature 9 is substantially perpendicular to thebase 1 and is controlled by a linkage arrangement. The linkagearrangement comprises two pairs of parallel arms, one pair of which 19,20 is shown in Fig. 3. The two pairs of arms are pivotally mounted onpins 21, 22 and 23, 24 attached respectively to the legs 15, 16 of theframe 11. The opposite ends of each pair of arms are pivotally connectedto similar pins 25, 26 (Fig. 3) attached to the side members. Thelocation of the pins 25, 26 is such that the arms are parallel to thebase when the armature is midway through its travel.

The inward movement of the armature 9, towards the base 1, is limited bythe legs thereof coming in contact with the electromagnet core. Theoutward movement, away from the base, is limited by means of stops 27,28, which are struck-up from the respective side members 2, 3 andlocated in the path of the leg flanges l7, 18.

The armature is normally urged to the outward position by helicalsprings 29, 3d. The springs are positioned by pins 31, 32 extending fromone end of the respective C-shaped side members to the other endthereof, passing through holes in the flanges and stops.

The forward part of the switch, to be described in'de tail hereinafter,includes the switching contacts which are opened and closed by operationof the armature. For example, if the switch is utilized for motorcontrol, two or more contacts are provided at one end of the switch forconnection to the line and a corresponding number of contacts areconnected to the opposite end for connection to the motor. The number ofcontacts required depends on the type of motor being controlled.

By way of example, I have shown a switch comprising four pairs ofaligned and spaced contacts 33, 34, 35 and 36 (Fig. 1). Wire connectors,such as shown at 37 are respectively connected to each of the contacts.Preferably a single screw, e.g. 38 (Fig. 3) is used to attach eachconnector-contact assembly to an insulator bridge member 39.

The bridge member 39, best seen in Fig. 5, is screwed at 40 into theside members 2, 3. The bridge member is provided with raised portions 41for separating adjacent pairs of contacts. The raised portions 41 areeach provided with a groove 42 for reasons to be discussed later.

Thus, the stationary contacts which are connected to the line and to themotor are mounted on the bridge member. The means for closing thesecontacts are carried by the armature 9.

As best seen in Figs. 2 and 6, an insulator contact carrier 43 isrigidly mounted on the outside of the armature frame 11 by means ofscrews 44. The carrier 43 comprises a base portion 45, and a pluralityof posts 46 which pass through holes in the bridge member. The number ofposts 46 corresponds to the number of pairs of stationary contacts; inthe illustrated embodiment four posts are employed.

A plurality of bridging contacts 47 (Fig. 3) are mounted respectively onthe posts 46. Each contact 47 is provided with an elongated holeslightly larger than the neck portion 48 of the post; the post beingcorrespondingly shaped. The contacts are supported on the shoulders 49of the respective posts and are spring urged against the shoulders byhelical springs 50. The springs are retained by cup-shaped caps 51. Thecaps 51 are each provided with an elongated slot which is adapted to fitover a correspondingly shaped head 52 of a retaining to prevent chatterbetween the cores during energization of the coil.

A cover 55 (Figs. 2, 3, and 7) is provided for the switch and is mountedby screw 56 (Fig. 2) to the bridge member 39. The cover is slotted alongthe opposite sides at 57 to provide access to the wire connectors. Theunderside of the cover is grooved at 58 to provide space for movement ofthe bridging contacts. On opposite sides of the grooves and extendingfrom one end to the other, rail-like extensions 59 are provided to fitinto the grooves 42 in the bridge member 39. This type of joint betweenthe cover and bridge member prevents arcing between adjacent contacts.

While I have described above the principles of my in vention inconnection with specific apparatus, it is to be clearly understood thatthis description is made only by way of example and not as a limitationto the scope of my invention as set forth in the objects thereof and inthe accompanying claims.

What is claimed is:

1. An electromagnetic switch, comprising a base member, a pair of sidemembers attached to opposite sides of Said base member, an E-shapedelectromagnet pin 53. The cap is mounted by depressing the cap againstthe spring slightly below the head, where the width of the slot isslightly greater than the thickness of the pin, and turning the cap 90degrees. The cap is preferably formed with a depression foraccommodating the head after the cap is turned 90 degrees. The retainingpins 53 may be molded in the posts or may be secured by any othersuitable means.

Theseparation between the bridging contacts 47 and the aligned spacedcontacts 33 is slightly less than the separation between the armatureand the electromagnet core. In this way, the bridging contacts are heldunder tension against the spaced contacts when the armature is drawn tothe electromagnet.

When it is desired to close the circuit between the line and the motor,the coil is energized, thereby converting thecore 4 into a magnet whichattracts the armature 9.

As best seen in Fig. 2 shading poles 54 are provided core mounted onsaid base member between said side members, a coil surrounding thecenter leg of the core and extending beyond the end thereof, an E-shapedarmature similar in shape to said electromagnet and movably mountedparallel to said electromagnet, the direction of movement being in aplane perpendicular to said base and the center leg of the armature corebeing dimensioned to be normally free of said coil when not attracted bysaid electromagnet and adapted to move into the extending portion ofsaid coil when attracted by said electromagnet, a frame member in theshape of a U, means securing said armature to the underside of the crossarm of said U, linkage arms pivotally connected to the opposite legmembers of said U and to said side members respectively, the connectionto the side members being such that the movement of said armature issubstantially linear and perpendicular to said base, an insulatingbridge member rigidly mounted on said side members, a plurality ofcontacts mounted in pairs in spaced alignment on said bridge member,contact carrying means attached to said armature and extending throughholes provided therefor in said bridge member, a plurality of bridgingcontacts secured to said contact carrying means and positioned to shuntrespective pairs of said spaced contacts, means positioned between saidbase member and said armature adapted normally to separate said armaturefrom said electromagnet, whereby said bridging contacts are separatedfrom said spaced contacts, and when said electromagnet is energized, thearmature is attracted thereto causing said bridging contacts to engagesaid respective pairs of contacts.

2. The switch according to claim 1, wherein said linkage arms comprise apair of parallel arms mounted to each side of said frame respectively,the arms of each pair being mounted parallel to each other and soconnected to the side members that when said armature is mid-way throughits travel the linkage arms are approximately parallel'to said base.

3. The switch according to claim 1, wherein the crossarm of the U shapedframe member comprises flanges engaging the opposite sides of saidarmature, the legs of the U having flanges extending respectivelytowards the side members, a stop extending from each of said sidemembers into the path of the respective leg flanges for limiting themovement of said armature away from said electromagnet, a pair of pinsfixed to said side members respectively and passing through holes insaid stops and end flanges, and a pair of helical springs positionedaround said pins respectively, between said flanges and said base,urging the endyflanges against said stops.

4. An electromagnetic switch, comprising aflat base member adapted to bemounted in the vertical plane, a

pair of C-shaped side members mounted so as to face each other atopposite sides on said base member, an electromagnet comprising anE-shaped core mounted on said base member between said side members, thelegs thereof extending perpendicular to and away from said base, a coilsurrounding the center leg of said core and extending beyond the endthereof, an armature movably mounted in front of said electromagnet andcomprising a similar E-shaped core member with legs thereof aligned withthe legs of said electromagnet core, the center leg thereof beingadapted to move into the extending portion of said core, a frame memberin the shape of a U, means securing said armature to the underside ofthe cross-arm of said U, the respective legs of the U extending towardssaid base and flanged at the ends thereof toward the side members,linkage arms pivotally connecting the respective legs of said U to theadjacent side members, the connection to the side members being suchthat the movement of said armature is substantially perpendicular tosaid base, a stop extending from each of said side members into thepaths of the respective leg flanges, for limiting the outward movementof said armature, a pair of pins fixed respectively to the side membersand extending from one end of the C to the other end, passing throughholes in said stops and end flanges, a pair of helical springspositioned around said pins respectively between said flanges and theinner ends of the C-shaped side members, thereby urging the end flangesagainst said stops, an insulating bridge member mounted rigidly on theouter ends of said C-shaped side members and spaced a given distancefrom said armature, a plurality of contacts mounted in spaced andaligned pairs on the outside of said bridge member, a plurality ofcontact supporting means in the form of insulating posts attached tosaid armature and extending through holes provided therefor in saidbridge member, a corresponding plurality of bridging contacts secured tosaid posts and positioned to shunt respective pairs of said spacedcontacts, the bridging contacts being separated from the pairs ofcontacts by operation of said helical springs, whereby when saidelectromagnet is energized the armature is drawn thereto, moving saidbridging contacts into contact with said spaced pairs of contacts.

5. The switch according to claim 4, and further comprising a covercomprising a plurality of rail-like projec tions on the undersidethereof, spaced to fit into grooves in said bridge member said pairs ofspaced contacts, whereby arcing between adjacent pairs is prevented.

References Cited in the file of this patent UNITED STATES PATENTS Re.20,676 Wilms et al. Mar. 22, 1938 2,304,972 Van Valkenburg Dec. 15, 19422,411,894 Peters Dec. 3, 1946 2,773,948 Pelz et a1. Dec. 11, 19562,794,093 Morschel May 28, 1957 2,823,280 Davies Feb. 11, 1958 2,853,577Scagnelli et a1 Sept. 23, 1958 FOREIGN PATENTS 752,870 Great BritainJuly 18, 1956

